Absorption through the skin

For an explanation of the transdermal image, we first have to take a closer look at our largest organ, the skin (with an area of 1.5 to 2 m2). As a barrier, the skin plays an important role in our immune system and prevents dehydration. At the same time, the skin excretes water, waste products and salt (in case of perspiration) and absorbs substances. This concerns small fat-free substances such as nicotine, but also electrolytes (salts, acids and their counterparts bases). Nothing new in itself and has long been applied. Just think of nicotine patches, hormone ointments or painkillers to apply.

The theory of the sweat glands

With regard to magnesium, there is now convincing evidence that it is also absorbed through the skin, at least in the natural chloride form such as the magnesium from Zechsal. Scientists are not yet in agreement about exactly how that works. The most compelling theory - about absorption through the sweat glands - is from Dr. Richard Danel of the Magnesium Health Institute. Several other researchers also think this is most likely.
Just like in the kidneys, there are groups of cells at the end of the sweat glands that recover magnesium when it wants to leave the body (via urine or sweat). The theory is that these cells not only stop magnesium, but also absorb it (at a sufficiently high concentration). We probably developed these special cells through the course of evolution. That also explains why we have not long since succumbed en masse to the magnesium deficiency.

Do you want to know all the ins and outs about this? Then you can read more on the website of the Magnesium Health Institute. 
Please note: scroll down for the text about "Assumed transdermal uptake of magnesium".  

What's the difference with pills?

Magnesium is still mostly used in pill form. There is nothing wrong with that in itself, but bear in mind that an estimated 60 to 70% of the magnesium is not used by the body. The stomach can only process a limited amount. The rest is removed through the kidneys, which is why there are often complaints of loose stools or diarrhea when using pills.
The absorption through the skin allows you to bypass the gastrointestinal tract. It is clear that transdermal uptake is rapidly gaining ground and that scientific interest in it is growing.